diff --git a/acinclude.m4 b/acinclude.m4
index 90afe8545908da8b33529be2afb093e30ac1fdca..fae9b81de88fcfefecdeaa4ee2a3a0aeb3c3c3f0 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -2686,10 +2686,10 @@ AC_DEFUN([CURL_CC_DEBUG_OPTS],
          WARN="-wd279,269,981,1418,1419"
          WARN=""
 
-         if test "$gccnum" -gt "600"; then
-            dnl icc 6.0 and older doesn't have the -Wall flag
-            WARN="-Wall $WARN"
-         fi
+         dnl if test "$gccnum" -gt "600"; then
+         dnl    dnl icc 6.0 and older doesn't have the -Wall flag
+         dnl    WARN="-Wall $WARN"
+         dnl fi
        else dnl $ICC = yes
          dnl this is a set of options we believe *ALL* gcc versions support:
          WARN="-W -Wall -Wwrite-strings -pedantic -Wpointer-arith -Wnested-externs -Winline -Wmissing-prototypes"
diff --git a/ares/acinclude.m4 b/ares/acinclude.m4
index 46b087c2dab5e7ad4b9511c3cc0348378cd845e7..9f772923924a6bc32accbf4baafd1edd8cbd5d67 100644
--- a/ares/acinclude.m4
+++ b/ares/acinclude.m4
@@ -1894,10 +1894,10 @@ AC_DEFUN([CURL_CC_DEBUG_OPTS],
          WARN="-wd279,269,981,1418,1419"
          WARN=""
 
-         if test "$gccnum" -gt "600"; then
-            dnl icc 6.0 and older doesn't have the -Wall flag
-            WARN="-Wall $WARN"
-         fi
+         dnl if test "$gccnum" -gt "600"; then
+         dnl    dnl icc 6.0 and older doesn't have the -Wall flag
+         dnl    WARN="-Wall $WARN"
+         dnl fi
        else dnl $ICC = yes
          dnl this is a set of options we believe *ALL* gcc versions support:
          WARN="-W -Wall -Wwrite-strings -pedantic -Wpointer-arith -Wnested-externs -Winline -Wmissing-prototypes"
diff --git a/ares/configure.ac b/ares/configure.ac
index f0e1a04fa39746cce940b6fdb070493867738790..666facd45d9a90821e6b4e8642176204c2e6526b 100644
--- a/ares/configure.ac
+++ b/ares/configure.ac
@@ -229,6 +229,12 @@ if test "$curl_cv_have_def___INTEL_COMPILER" = "yes"; then
   dnl On Linux this compiler uses gcc's header files, so
   dnl we select ANSI C89 dialect plus GNU extensions.
   CPPFLAGS="$CPPFLAGS -std=gnu89"
+  if test "$curl_cv_def___INTEL_COMPILER" -gt "600"; then
+    dnl Show errors, warnings, and remarks
+    CPPFLAGS="$CPPFLAGS -Wall"
+    dnl Perform extra compile-time code checking
+    CPPFLAGS="$CPPFLAGS -Wcheck"
+  fi
   dnl Change some warnings into errors
   dnl #140: too many arguments in function call
   dnl #147: declaration is incompatible with 'previous one'
diff --git a/configure.ac b/configure.ac
index 5654a49594bf1547c46981ce4915107cabdbdcbc..c07052a562cbd5135b473af7462ca57e7bf3ea4e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -303,6 +303,12 @@ if test "$curl_cv_have_def___INTEL_COMPILER" = "yes"; then
   dnl On Linux this compiler uses gcc's header files, so
   dnl we select ANSI C89 dialect plus GNU extensions.
   CPPFLAGS="$CPPFLAGS -std=gnu89"
+  if test "$curl_cv_def___INTEL_COMPILER" -gt "600"; then
+    dnl Show errors, warnings, and remarks
+    CPPFLAGS="$CPPFLAGS -Wall"
+    dnl Perform extra compile-time code checking
+    CPPFLAGS="$CPPFLAGS -Wcheck"
+  fi
   dnl Change some warnings into errors
   dnl #140: too many arguments in function call
   dnl #147: declaration is incompatible with 'previous one'